The deterioration of water quality, overexploitation of freshwater resources, hydrological hazards and adverse effects of landscape degradation and sectoral management pose a risk to human health and to economic and social development. On the other hand, this also affects the functioning of ecosystems and their ability to provide goods and services on which human well-being depends.

Therefore a better understanding of water as both an abiotic resource and a service delivered by ecosystems is needed. This understanding would make it possible not only to identify and quantify the critical linkages that regulate the interrelationships of hydrology and biota, but also to see how the control of these linkages may contribute to environmental sustainability. Today, the management approach has to go beyond protection and restoration and recognize the carrying capacity of ecosystems in the face of increasing human impact, find ways of improving and transferring solutions across a variety of environments.

Ecohydrological research should be strengthened for improving the understanding of groundwater/surface water interactions in the critical areas of catchments (e.g. wetlands, river corridors, ecotone zones) and the role of feedbacks between ground/surface water and vegetation as a regulatory tool. Special emphasis should be given to ecohydrological processes in critical areas, such as arid/semi-arid zones and estuaries/coastal zones and to groundwater-dependent ecosystems (GDE) for which further research is needed for their identification, inventory and assessment. Many regions in the world and in particular coastal areas are rich in GDE with coastal and terrestrial wetlands, of high ecological and socio-economic values. Many of these wetlands are however drying up and becoming salinised, polluted and increasingly groundwater dependent and eutrophisized with consequent decline in the hydrogeological functioning, and loss in ecological values.

The main impacts on these coastal ecosystems are intensive groundwater exploitation, waste water spilling, channelization, and proximity to urban areas. As a consequence, many of these wetlands have been modified and their current behaviors have severely changed from the unperturbed functioning under natural conditions. In order to manage these wetlands properly, an action strategy needs to be designed that allows identification of the best option for wetland conservation.

For the best option to be successfully implemented, however, water management objectives and scenarios based on this new knowledge so generated must build on multi-stakeholder consensus. Scientists can provide the required expertise on how basins evolve under various flow conditions but it is the water users who can say what rivers and aquifers are used for and how much water they need.

Furthermore, establishing an adaptive management approach based on learning by doing is another critical aspect that stems from the uncertainties inherent to these water linkages and the exchange with ecosystems. As a tool for equitable allocation of water based on available supply, environmental flows are particularly fit for this purpose, provided that they can only ensure a healthy basin if part of a broader package of measures such as soil protection, pollution prevention, conservation of habitats and rain harvesting techniques. The success or failure to mainstream environmental flows in water management will also depend on whether they can find their place in national legislation and institutional reforms. This is where regionally defined principles and practices and the role of knowledge networks will be the most effective. FINAL 3 1 2 TAP - eFlows and UNESCO IHP